Combined superheater and boiler



" y 17, 1932; w. H. ARMACQST 5 counnwn SUPERHEATER AND Burma Filed Jan.21. 19:50 2 Sheets-Sheet 1 6. INVENTOR- Wl/fiur fi/macad'f a .Z

' ATI'ORN EY Filed Jan. 21, 1930 2 Sheets-Sheet 2 ooooooQ INVENTORM/fiur flf/rmaumf a? Que ATTORNEY wrmmn n. ARMACOST, or

Patented May 17, 1932 NEW xonx, n.

Y., assIen'oa 'ro 'rnn surnam'rna courm,or NEW YORK, m

commnn surnnnnarrm Ann 301mm Application fll edl'anuary 21, 1930. SerialNo. 422,329.

My invention-relates to the art of-steam production and aims to providean efficient arrangement .of superheater and bo1ler adapted foreconomical manufacture, mstallation and operation.

In sup lylng superheated steam to prlme movers fiom combinedsuperheaters and boilers having common furnaces, difliculty has beenexperienced in maintaining the temperature variations of the superheatedsteam within desired limits at different rates ofv firing.

It is an object of my invention to provlde a combined superheater andboiler adaptedto avoid such difliculty.

In accordance with the aims above stated,

a superheater boiler installation within my invention may comprise asuperheateryboiler and furnace having the superheater elements arrangedin two groups, one of which is so ositioned with respect to the furnaceand oiler that it receives a considerable portion of its heat byradiation from the furnace and the other group of elements arrangedsothat it receives the most of its heat from the combustion gases from thefurnace and so that the percentage of surface area of the second groupof superheater elements in the stream of combustion gases from thefurnace increases with an increase'in rate of firing of the furnace.Furthermore, the boiler'is preferably connected to the two groups ofsuperheater elements so that the saturated steam flows from the boilerinto the group subjected to thegreater amount of radiation and then intothe group of elements receiving its heat primarily from the furnacegases, the two groups being in series in the path of the steam flow. Itis a feature of my invention also to so arrange the group of superheaterelements receiving the greater amount of radiation that the percentageof its surface area lying in the stream of combustion gases changes verylittle with ordinary changes in rate of firing of the furnace. In

practical installations, it has been found desirable to place theconvection group of. superheater elements outside of the steamgenerating tubes and the radiant group of superhea-ter elementsintermediate the bank of generating tubes nearest the fire. The novelfeatures of my invention are pointed out with particularity in theappended claims. The invention, however, to-

gether with further objects and advantages, will best be understood froma scription of an illustrative arrangement of a combined superheater,boiler and furnace embodying the invention andsuch a descri tion willnow be given in connection with t e accompanying drawings in which aFig.1 is a sectional elevation through a cross drum boiler havingsemi-vertical tubes combined with a superheaterfand furnace inaccordance with my inventiontFig. 2 is an enlarged section on theline'22 of Fig. 1

- looking in the direction of the arrows.

Referring to the drawings more in'detail, the illustrative embodiment ofmy invention therein shown comprises a boiler having upper drums 10,12,connected by water tubes to' a lower drum 14, said tubes comprising afront bank 16 and rear banks 18 and 19. The front wall of the boilersettin is shown at 20 and below the drum 14 and tubes 16 is a furnacechamber 22. The bank of tubes 16 is shown in semi-vertical. position andas inclined forwardly from the vertical to some extent in passing fromthe lower drum 14 to the upper drum 10, so that the upper end of bank 16lies nearer the front wall 20 than the lower end and the upper drumlO isin front of lower drum 14. A bafile 24 is shown at the rear of bank 16running parallel to the tubes of such bank and arranged to direct thecombustion gases from furnace 22, in

lar e measure, longitudinally of the tubes in suc bank.

I In addition to the bank of tubes 16, drums 10 and 14 are shown asconnected by a set of tubes 26 lying in front of the bank 16. At theirpoint of exit from drum 14, tubes 26 are shown as running almosthorizontally, but a short distance from drum 14 such tubes inclineupwardly somewhat from the horizontal and extend forward nearly to thefront wall 20. Near the front wall, tubes 26 curve upwardly and thenre-curve toward the bank 16, running from near the front wallsomedetailed d'ee what upwardly to a point 28 near the bank 16 andthence extending upwardly to the drum 10 parallel to such bank so as toleave a space 29 between their upper portions and wall 20.

The elements of the superheater are shown as divided into two groups,one of which is designated as 30 and lies within the space outlined bythe tube bank 16 and the upper portions of tubes "26. Elements in group30 run parallel to the tubes of bank 16 and are fastened to tubes ofbank 16 and additional tubes 26 by straps 31, 31. Elements of group 30extend downwardly toward the furnace 22 so as to receive considerableheat by direct radiation from the furnace.v Furthermore, elements ofroup 30 are so interspersed in the tubes of bank 16, and the bank 16 andbaffle 24am so arranged that the major portion of the surface area oftheelements of group 30 lies intbe stream of combustion gases from furnace22 even at low firin rates of the furnace, whereby the total 0 heatunits imparted to the steam by the elements of group 30 changesverylittle with ordinary changes in the rate of firing. A suitablearrangement of tubes 16 and 30 for such purposes is illustrated indetailin Fig. 2. As shown, the tubes in bank 16 and the additional tubes26 are 3 outside diameter and are spaced 6% between centres both in thedirection parallelto baffle 24 and in the direction at-right angles toit.. Tubes in group 30 may be either of 1%" or 1 inside diameterwhenused with tubes 16 of the size and arrangement above stated and arearranged preferablyparallel to tubes 16 in rows running at right anglesto bafile24 and spaced somewhat closer together within bank 16 than inthe space between bank 16 and tubes 26 and between tubes 26. Each row oftubes 30 preferably contains four tubes in the space within tube bank 16and two tubes outside such bank,one between bank 16 and tubes 26 and onewithin the space outlined by tubes 26. g I

A second group 32 of superheater elements is shown in the space 29intermediate the upper ends of the additional tubes 26 and the frontwall 20. Elements of group 32 are held together by transverse braces 34,34, and the lower end of the-front elements of such group are supportedon an angle 35 fixed to the recurved portion'of the water tubes 26 whilethe upper ends of the front elements of such group rest on angle 37fixed to the front wall 20. It will be seen that the elements of group32 are so placed that only a minor portion of their surface area liesinthe stream of combustion gases from furnace 22 at low firing rates ofthe furnace but that, as the rate of firing of the furnace is increased,the stream ofgases is thereby widened to increase the portion of thearea of such elements in amount of contact with the gases of combustherelativefliy large amount of shielding from radiation :1 orded them bythe re-curved por: tions-of the additional tubes 26.

The groups of elements 30 and 32 are connected in series in the path ofthe steam flow and, in accordance with my invention, the group 30receives the saturated steam direct from the boiler, thereby protectinggroup 30.

against overheating. For this purpose, saturated steam is conducted fromthe rear drum 13 of the boiler through a steam pipe 36 to a header 38 towhich the elements of grou 30 are connected by the steam leads 40. Theother ends of the elements of group 30 are connected to a second header42 by steam loads 44. From header 42 steam may be conducted to thesuperheater elements 32 by steam leads 46, the other ends of elements ingroup 32 being connected to a third header 48 by means of steam leads50. From header 48 the steam may be conducted to the prime mover, orother steam consuming apparatus by means of a pipe 52. I

If desired, additional water heating sur- I face maybe supplied by meansof to es 54 7 below the combustion zone and connected between a rearheader 56 and a front header or drum 58, steam from drum 58 passing intodrum 10 through pipe 60.

A steam generating apparatus, designed and operating on the principlesabove de-,;

scribed is capable of supplying large quantities of steam at a highdegree of Sn erheat but with relatively slight variations 0 super.- heatwith changes in boiler rating. Moreover, the super-heater elements havea comparatively long life. i

I claim: v

1. The combination of a furnace, a boiler heated thereby, two groups ofsuperheater elements, one of which is arranged to receive a relativelylarge amount of radiant heat from said furnace as compared to the other,said other group of superheater elements so arranged with respect tosaid boiler and furnace that the percentage of its surface in the streamof combustion gases from the furnace increases automatically withincrease in rate of operation of the furnace, and connections leadingsteam from the boiler first through said radiant group of elements andthen surface within the gas stream at low rates of firing, said othergroup of superheater ele niatically with increase in rate of operationof the furnace, and connections leading steam from the boiler directlyto said radiant group and there to said other group of superheaterelements.

3. The combination with a furnace, of a boiler having an inclined bankof water tubes arranged to receive radiant heat from said furnace at oneend, a bafiie arranged to direct the combustion gases along said tubes,a group of superheater elements extending parallel to said tubes intothe zone of radiant heat and so interspersed among said water tubes asto restrict the volume of gases flowing through the space outlined bythe tube bank and elements to prevent material variations in the amountof heat absorbed by such group with variations in rate of steamgeneration, a second group of superheater elements relatively shelteredfrom radiation and so arranged that the combustion gases from saidfurnace 'flow automatically over a greater ercentage of its'area withincreasing rates of combustion, and connections for leading steam fromsaid boiler through the elements of said groups.

4. The combination of a boiler comprising an upper drum, a lower drum,and a front bank of semi-vertical water tubes connecting said drums, abafiie extending upwardly from said lower drum along the rear of saidbank, additional water tubes connecting said drums and extendingforwardly from said lower drum, and then recurving toward said bank, agroup of superheater elementsinterspersed in the tubes of said bank andrunning parallel therewith, a second group of superheater elements lyingabove the recurved portion of said additional tubes, and steamconnections between said boiler and groups of elements.

5. A boiler as set forthin claim 4 together with means leading saturatedsteam directly from the boiler to the interspersed group of elements andfrom the interspersed group to the second roup of elements.

6. The com ination of a boiler having a lower drum, an upper drum infront of said lower one and a. front group of water tubes connectingsaid drums, a group of superheater elements interspersed in said tubes,a second group of superheater elements in front of said tubes, and steamconnections between said boiler and groups of elements.

7. The combination of a furnace, a boiler heated thereby and having alower drum and an upper drum in front of said lower one, and water tubesconnecting said drums, the front ones of said tubes running forwardlyabove the furnace and then recurvingtoward theothers, a group ofsuperheater elements interspersed in said tubes, a second-group ofsuperheater elements in front of the upper portions of said tubes andabove the recurved portion of said front tubes, and steam connectionsbetween said boiler and groups'of elements. r

'8. The combination as set forth in claim 6 and in'which the steamconnections lead the steam from the boiler directly to the group ofsuperheater elements among the water tubes and then to the group infront of the'water tubes.

i 9. The combination assetforthin claim 7 and in which the steamconnections lead the steam fromthe boiler directly to the group ofsuperheater elements among the water tubes and then to the superheaterelements in front of the water-tubes.

10. The combination as set forth in claim 6 and in which the water tubesare so ar ranged with respect to the elements interspersed therein thatthe amount of gases contacting with the inters ersed superheaterelements varies relative y. little compared withvariations of boilerrating throughout the ordinary range of such variations.

11. The combination of a furnace, a boiler heated thereby, two groups ofsuperheater elements both directly above said furnace, one of saidgroups being arranged to receive a relatively large amount of radiantheat from said furnace as com ared to the other,

said other group of super leater elements being so arranged with respectto said boiler and furnace that the percentage of its surface in thestream of combustion gases from the furnace increases automatically withincrease in rate of operation of the furnace, and connections leadingsteam from the boiler first through said radiant group of elements andthen throu h said other group.

12. The combination of a furnace, a boiler heated thereby and having anup-pass for gases from said furnace, two groups of superheater elementsboth in said up-pass, one of said groups being arranged to receive arellarge amount of radiant heat from ativeiyI .said rnace as compared tothe other, said other group of superheater elements so arranged withrespect to said boiler and fur-' nace that the percentage of its surfacein the stream of combustion gases from the furnace increasesautomatically with increase in rate of operation of the furnace,

and connections for leading steam from the boiler having an inclinedbank of watert tubes arranged to receive radiant heat from said furnaceat one end, a bafiie arranged to direct the combustion gases along saidtubes,

6 a group of superheater elements extending parallel to said tubes intothe zone of radiant heat and so interspersed among said water tubes. asto restrict the volume of gases flowing through the space outlined bythetube.

10 bank and elements to prevent material vari- 1 atio ns in the amountof heat absorbed by such group with variations in rate of steamgeneration, a second oup of superheater elements arranged at sustantiallythe same distance from the-furnace as a portion of said firstgroup,but relatively sheltered from radiation and so arrangedtha't thecombustion gases from said iurna'ce flow automatically over a greaterpercentage of its area with in- 201'CIe8S1I1g rates of combustion,and-connections I I i the elements ofsai'dlgrou s.

, for leading steam from said boiler through R 'Aitmoosr

